1.Field of the Invention
The present invention relates to purification and classification methods, and more particularly relates to the purification and classification of dispersions containing colloidal particles.
2. Description of the Art
In processes which form stabilized colloidal particles (e.g., carbon black having attached an organic group containing at least one ionic group or one ionizable group), free species can co-exist in a dispersion. While such dispersions can be used in subsequent end uses such as in inks or paints and especially inkjet inks, it is desirable to remove impurities like free species from the dispersion since a purified dispersion can improve properties in the desired end product application.
Accordingly, it is desirable to develop processes which permit the purification and classification of dispersions containing stabilized colloidal particles and free species.